Field of the Invention
The present invention relates to an illumination system for a projection device, especially an illumination system for a stereoscopic projection device. In particular, the present invention relates to an illumination system comprising a color wheel module which includes a plurality of wave band transmitting transforming areas and a plurality of wave band reflecting transforming areas.
Descriptions of the Related Art
Stereoscopic projection devices have been widely used in various presentations and performances to display lively stereoscopic images so that viewers can feel as if they were personally on the scene.
Conventional illumination systems for stereoscopic projection devices usually have a color wheel and a color filter. First, a plurality of lights of the three primary colors is generated by means of an illumination source of the illumination system through a color wheel. The lights are transformed by a color filter into a plurality of lights of two different wavelengths. The lights of two different wavelengths are then transformed by an imaging system of the projection device into a left-eye viewing angle image and a right-eye viewing angle image respectively. Thereby, viewers can achieve the desired effect in which the left eye receives the left-eye viewing angle image and the right eye receives the right-eye viewing angle image by simply wearing a pair of passive eyeglasses. The brain of the viewer will automatically combine the left-eye viewing angle images and right-eye viewing angle images into a stereoscopic image.
However, because the aforesaid conventional illumination system has a color wheel and a color filter, it is impossible to miniaturize the volume of the stereoscopic projection device which comprises the conventional illumination system. In addition, the lights of the three primary colors will be projected to the color filter at different incident angles. If the lights are not projected to the color filter at an angle which is almost perpendicular to the color filter, then the lights of undesired wavelengths tend to be generated through transformation. That is, image cross-talk is likely to happen. Image cross-talk refers to the situation when the right eye of the user will see the right-eye viewing angle image and part of the left-eye viewing angle image simultaneously, or vice-versa.
Accordingly, it is important in the art to provide an illumination system for a stereoscopic projection device that can improve the aforesaid shortcomings and avoid image cross-talk.